# US 4,399,727 A · Drum shear

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- Number: US 4,399,727 A
- Document ID: US4399727A
- Status: Granted
- Kind: A
- Application number: 06/228,699
- Filed: 1981-01-26
- Granted: 1983-08-23
- Earliest claimed: 1980-02-20
- Assignees: Mitsubishi Jukogyo Kabushiki Kaisha
- Inventors: Shunji Omori; Kanji Hayashi; Yukio Hiasa; Nobutaka Maeda; Shoichi Hashimoto; Hiroki Yoshiya
- Web page: https://patentgrep.com/patent/US4399727A

## CPC

- B26D 7/14: by tensioning the work
- B23D 25/12: Shearing machines with blades on coacting rotating drums
- Y10T 83/0515: During movement of work past flying cutter
- Y10T 83/4836: With radial overlap of the cutting members
- B26D: CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING (for growing crops or plants A01D, A01G; for fodder or straw A01F; for bulk butter A01J; for dough A21C; slaughtering A22B; for tobacco, cigars or cigarettes A24; marking-out, perforating or making buttonholes A41H25/00; manufacturing footwear A43D; brushmaking A46D; surgery A61B; disintegrating, mincing or shredding in general B02C; cutting wire, making pins or nails B21F, B21G; of the kind used formetal B23; cutting by abrasive fluid jets B24C5/02; hand-held cutting tools B26B; perforating, cutting-out, stamping-out or punching, or severing by means other than cutting B26F; for wood B27; for stone B28D; working of plastics or substances in a plastic state B29; making boxes, cartons, envelopes or bags, of paper or similarly worked materials, e.g. metal foil, B31B; article or web delivery apparatus incorporating cutting or line-perforating devices B65H35/00; for leather or upholstery B68, C14B; for glass C03B; making matches C06F; for peat C10F; for sugar C13B45/00; for textile materials D06H; civil engineering, building, mining, see Section E; for light guides G02B6/25; cutting processed photographic material G03D15/04)
- B23D: PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR (making toothed gears or the like B23F; cutting metal by applying heat locally B23K; arrangements for copying or controlling B23Q)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A drum type shear includes a pair of rotatable drums, each drum including a shearing blade. The circumferential velocity of the outer edge of a first blade is greater than the circumferential velocity of the outer edge of a second blade, such that upon rotation of the drums with a workpiece passing therebetween, after the workpiece has been initially bitten between the blades, shearing of the workpiece is completed while the outer edge of the first blade overtakes the outer edge of the second blade.

## Claims

### Claim 1

In a drum shear for shearing a workpiece, said drum shear being of the type including a pair of rotatable drums, each said drum including a longitudinal shearing blade, and said drums being arranged such that upon rotation of said drums a workpiece passing therebetween is bitten between and sheared by said blades, the improvement wherein:
said drums rotate at equal angular velocities;
a first radial distance between the outer edge of a first said blade and the rotational axis of the respective first said drum is greater than a second radial distance between the outer edge of a second said blade and the rotational axis of the respective second said drum, the ratio of said first radial distance to said second radial distance being 1.02 to 1.20, such that the circumferential velocity of said outer edge of said first blade is greater than the circumferential velocity of said outer edge of said second blade; and
said first and second drums being rotated by drive means such that at the beginning of an operation of shearing a workpiece said outer edge of said first blade first contacts the workpiece at a first longitudinal position along the direction of movement of the workpiece, said outer edge of said second blade first contacts the workpiece at a second longitudinal position along said direction of movement, and said first longitudinal position is upstream of said second longitudinal position with respect to said direction of movement, thereby defining a gap extending upstream from said outer edge of said second blade, such that during the shearing operation said outer edge of said first blade moves in a direction relative to said outer edge of said second blade to sequentially reduce the size of and eliminate said gap, and such that upon completion of the shearing operation said outer edge of said first blade is downstream of said outer edge of said second blade with respect to said direction of movement.

### Claim 2 (depends on 1)

The improvement claimed in claim 1, wherein said first drum is positioned above said second drum.

### Claim 3 (depends on 1)

The improvement claimed in claim 1, wherein said second drum is positioned above said first drum.